British lawyers have called on the Ministry of Defence (MoD) to investigate the alleged shooting of four "innocent" Afghan youngsters while they were drinking tea in their family's mud home in Helmand province.

Tessa Gregory, of Public Interest Lawyers, said the firm was acting for the elder brother of two teenagers killed in the incident.

Ms Gregory said the "innocent" young people were shot during a joint British-Afghan security operation on October 18.

"Our client, the elder brother of two of the teenage victims, wants to know why this happened. As far as we are aware no investigation into these tragic deaths has taken place. We hope that in light of our urgent representations the Ministry of Defence will act swiftly to ensure that an effective and independent investigation is carried out without any further delay."

The victims, all boys, were aged between 12 and 18.

A summary of the allegations claims that at about 8pm that evening, British and Afghan forces entered the village of Loi Bagh. The soldiers allegedly walked through the village calling at various houses asking to be told where the claimant's brother Fazel Mohammed lived.

It is claimed the soldiers entered the house of a neighbour, dragged him from his bed, hooded him and his son and beat them until under questioning they showed them the house of Fazel, which was across the street.

The summary says the four victims were Fazel Mohammed, 18, a shopkeeper, and Naik Mohammed, 16, a farmer, both of Loi Bagh village, who are younger brothers of the claimant, plus schoolboys Mohammed Tayeb, 14, and Ahmed Shah, 12, of Nad-e-Ali District, Helmand province.

The soldiers allegedly ransacked the house, searching for incriminating evidence but left after they were unable to find anything. It is claimed they remained in the property for about two hours. No attempts were made to arrest or detain any of the claimant's family, the summary says.

An MoD spokesman said: "The Ministry of Defence received details of these allegations on Tuesday in a letter from a UK firm of solicitors on behalf of an Afghan national and will give them full consideration before responding."